Ground-based portable and collapsible structures

Abstract

A ground-based portable and collapsible structure comprises two similar rectangular plates hinged together and disposed in downwardly-diverging relationship with their hinge-remote edges engaging the bottoms of re-entrant slots opening from the upper edges of spaced and parallel bar means of inverted T-section disposed on the ground transverse to said plate edges. Each bar means may be an inverted T-section bar or two L-section bars secured to one another with their vertical webs mutually opposite and spaced, preferably by spindles on which spiked metal strips are mounted for pivotal movement between a first position wherein it is accommodated in said gap and a second position wherein it projects downwardly from the L-section bars, the two strips being offset one to each side of the median plane bisecting said gap and being maintained in such dispositions by spacers mounted on the spindles alongside the strips.

I claim: 
     
       1. A ground-based portable and collapsible structure, e.g. a road sign, comprising two similar substantially rectangular plates hinged together and to be disposed in use in downwardly-diverging relationship with restricting means joining the two plates remote from the hinge axis to limit the angle to which the plates can open from one another, characterised in that the restricting means comprises a pair of bar means to be disposed in use on the ground in spaced and parallel relationship and affording respective pairs of upwardly-opening re-entrant slots which by alignment of the bar means may be brought into precise registry in two upwardly-converging planes intersecting at an angle of at least about 60° and at most about 75° and in which are engaged the hinge-remote edges of the plates. 
     
     
       2. A strusture as claimed in claim 1, wherein each bar means comprises a T-section bar with said slots being provided in the stem-forming web of the bar. 
     
     
       3. A structure as claimed in claim 1, wherein each bar means comprises two L-section bars secured to one another with their vertical webs mutually opposite and spaced. 
     
     
       4. A structure as claimed in claim 3, wherein the L-section bars are fixedly secured to one another by two spindles each bridging the gap between said vertical webs somewhat inwardly of a different one of said re-entrant slots. 
     
     
       5. A structure as claimed in claim 4, wherein a spiked metal strip is mounted on each spindle for pivotal movement between a first position wherein it is accommodated in said gap and a second position wherein it projects downwardly from the L-section bars, the two strips being offset one to each side of the median plane bisecting said gap and being maintained in such dispositions by spacers mounted on the spindle alongside the strips. 
     
     
       6. A structure as claimed in claim 5, including means for locking the spiked metal strips in both said first and second positions. 
     
     
       7. A structure as claimed in claim 1 or any one of claims 2 to 6, wherein elastomeric material is adhered to those surfaces of said bar means which in use are in contact with the ground.